Automatic pressure regulator



Oct. 8, 1929. H. F. MacMlLLlN 1,731,145l

AUTOMATI C PRES SURE REGULATOR Filed Dec. 30, 1926 Y Patented Oct. 8, 1929 nowann E nacnILLnr, F MOUNT GILEAD, on'ro AUTOMATIC PRESSURE -iaiietrLaTon.

Application led December 30, 1926. "Serial No. 158,027.`

This invention relates to a pressure regullator particularly adapted for use with high pressure hydraulic service. It has a dual function and not only relieves the pump when the pressure ,in the entire system reaches a predetermined limit, -but also maintains a definite pressure at the point of applicationv I 2o is opened so that the pump runs idly and the uid is by-passed through a return pipe back to the pump. At the same time a check valve maintains the pressure at the point of application.

Further details of the invention will be apparent from the following description and the appended claims.

In the drawings:

Figure 1 is a side elevation of the automatic pressure regulator.

2-2 of Figure 1.

A frame or casting 1 has a lower cross bar 2 and a cross bar 3 intermediate its ends. In the upper end of this frame is mounted a valve casing 4 which may be fastened to the frame by bolts 5 or in any other desired manner. This valve casing has an inlet 6 which is connected tothepump and communicates with a chamber 7 having a communication with a by-pass 8 which leads to the return pipe 9 which goes back'to the suction reservoir of the pump or to an exhaust line such as sewer. Communication between the cham? bers 7 and the by-pass 8 is controlled by means of a by-pass relief valve 10. From the chamber 7 a second passage 11 communicates with a chamber 12 through the medium like, as may be desired. of supply or exhausting it into a sewer or the Figure 2 is a vertical section onthe line of a check valve 13 and this chamber 12 is connected by a pipe 14 to the press. From the foregoing it will be observed that the inlet'pipe 6, the chamber 7, and the passage 11 constitute a conduit serving as a source of pressure fluid supply; and that the pipe 14 and the chamber 12 constitutel a conduit for discharge of pressure fluid to a point of use. The check valve 13 controls the flow of fluid between the two conduits in such a way that fluid can flow through the valve in only one direction, namely, from lthe supply conduit to the discharge conduit. 4It willalso be observed that the by-pass relief valve 10, when open, diverts the pressure luid from the 'discharge conduit, eitherreturning the fluid to the source of supply or exhausting it into a sewer or .the like, as may be desired.

Carried by the lower end of the frame 1 is a'member 15 which may be fastened to said A70 the piping 18is always uniform.

A rod19 is slidably mounted in the cross bar 3 of the frame 1 and in the member 15 and has its lower end projecting into the chamber 17. Suitable packing 21 is provided which is held4 in position by a packing nut 21 which also acts to guide the rod 19 in its movements. Intermediate its ends this rod is provided with a threaded portion 22 screw threaded on which is an adjusting nut 23 and a lock nut 24. A heavy coil spring surrounds the rod-and one end of the same bears against the adjusting nut 23 while the other end bears against the cross bar 3. The spring 25 tends to force the rod 19 downward, but its movement in this direction is limited by a nut 27 engaging the upper screw threaded end 26 of the rod on the uppe/r side of the cross bar 3.

A smaller rod 28 is guided at its upper end the valve casing 4 by means of packing 29 and a packing nut 30. The lower end o f this rod fits slidablywithin 'a small chamber 31 formed in the upper end of the rod 19.` The lower end of the rod 28 is provided 4with an enlargement 32 above which is a washer 33 which is positioned between the upper end of the rod 19 and a nut 34 which is screw threaded on the screw threaded portion 26 of the rod 19. vIn this manner the rod 28 may have a certain amount of longitudinal movement relative to the rod 19, but at other timesi is forced to move in unison with said rod 19.

A spring 35 surrounds the rod 28 and bears at one end against the top of the nut 34: and at its other end against an enlargement 36 on the rod 28. This spring tends to move the rod 28 upward, but its movement in this direction is limited by the engagement of the enlarged lower end 32 with the washer 33. When in normal position the upper end of the rod 28 lies just below the relief valve 10 when the latter is in closed position.

Assuming that the parts are in the posi- Vtion shown` in Figures 1 and 2 and that the spring 25 has been adjusted for the desired pressure then when the pump is placed in operation, 'fluid under pressure will be forced chamber 17 beneath the rodl 19. At all times the pressure in the chamber 17 will be substantially the same as that exerted upon the press.

This pressure on the lower end of the -rod 19 will tend to move the rod upwardly against the tension of the spring 25. During the first part of this movement the rod will move upward relative to the, rod 28 and the spring 35 will be tensioned, but the tension' o'f this spring itself is not suflicient'to lift the valve 10 from its seat against the pressure of the fluid in the chamber 7. When the rod .19

cavity 3l comes in Contact with the end 32 of the lrod. 28, the next succeeding movement of the rod 19 will also move the rod 28 and as soon as the relief valve 10 is lifted slightly 'from its seat, the spring 35 will operate to lift the check very quickly.

The fluid under pressure will then pass from the chamber 7 into thevchamber 8 and through the return pipe 9 back to the suction /reservoir of the pump or to an exhaust line 0 such asfa sewer, thus taking the load off the pump. The pressure in the line to the press, however, will then be exerted on top of the .check valve 13 and immediately close the same, maintaining the pressure in,y the press chamber 12, piping 18, and chamber 17 uniform. Whenever this pressure drops below a predetermined point, the spring 25 will force the rod 19 back toward the position shown in the drawings and in this movement the rod 28 will be drawn with the rod 19, thus allow- .ing the check valve 10 to be seated bythe force of gravity or the that whenl the predetermined pressure is reached, the 'load will be taken off .the pump,y

while at the same time the desired pressure WillI be maintained in the press. The automatic regulator, therefore, not only supplements'the safety valve as a protective device but at the same time also acts to unload and relieve the pump and to maintain the desired pressure at the point of application and performs all of these functions eiliciently.

Minor details may be modified without in any way departing from the spirit of the invention, lwhich is to be regarded as limited only by the scope of the appended claims.

I claim as my invention:

, 1. In an automatic pressure regulator, a conduit serving as a source of pressure fluid supply, a conduit for discharge of pressure fluid to. a point of use, a valve to control the flow from one conduitto the other, a by-pass relief valve in the supply conduit for diverting the pressure fluid from the discharge line, and means for opening said relief valve comprising a slidably mounted rod, means for subjecting one end of the rod to the same pressure as that in the discharge line, spring means tending to move the rod in the other direction, a second rod having a lost motion connection with the first and having its end directly underlying said check valve, and spring means tending to move the second rod toward said check valve.

2.In an automatic pressure regulator, a conduit serving as a source of pressure fluid Y supply, a conduit for discharge of' pressure has moved upward until the lower end of the f1 uid to a point of use-,a valve to controly the flow from one conduit to the other, a ley-pass relief valve in the supply conduit for diverting the pressure fluid from the discharge line, and means for opening said relief valve comprising two slidably mounted rods having lost motion connection, ,the end of one rod directly underlying the check valve and the opposite end of the other rod being subjected to the same pressure as that in the discharge line, a spring tending to force the first rod toward the check valve, and a stronger spring tending to. force the other rod away from the check Valve and against the fluid pressure.

In testimony whereof, I have hereunto subscribed my name.

HOWARD E. MACMILLIN. 

